解
lg(√54)
=lg3√6
=lg3*√2*√3
=lg3+lg√2+lg√3
=lg3+lg[2^(1/2)]+lg[3^(1/2)]
=lg3+1/2*lg2+1/2*lg3
=b+1/2*a+1/2*b
=3/2*b+1/2*a